Electric switch



D. M. SCHIFFERT.

ELECTRIC SWITCH.

APPLICATION FILED MAR. 9, 1918,

1,393,836. Patented Oct. 18, 1921.

2 SHEETS-SHEET l- D. M. SCHIFFERT.

ELECTHH) SWITCH.

APPLICATION FILED MAR-9.1918.

Patented Oct. 18, 1921.

2 SHEETSSHEET 2.

fin/871202,

i Nu DANIEL M. scnmrna'r, onnosroN, massacnnsnms, ASSIGNOR 'ro SEARS'B.conm'r,

JR OF BOSTON, MASSACHUSETTS.

- ELECTRIC SWITCH.

Specification of Letters Patent.

Patented Oct. 18, 1921.

Application filed March 9, 1918. Serial No. 221.347.

To allwhomit may concern:

Be it known that I, DANIEL M. SCHIF- FERT, a citizen of theUnitedStates, residing in Boston, county of Suifolk, and State ofMassachusetts, have invented an Improvement in Electric Switches, ofwhich the following is a specification;

My invention relates to switches or circuit breakers in which thecontacts are broken in air.

Electric switches adapted to automatically open upon an abnormal currentcondition in the circuit they are designed to control are commonlyprovided with means responsive to such abnormal condition to operate alatch or break a toggle to thereby cause the movable member of theswitch to move to open position, usually under the influence of aspring.

If a latch is employed to normally restrain the movable switch member inthe closed position of the switch, there is usually considerablepressure exerted upon the latch by the spring in such closed positionand a comparatively great force must be exerted upon the latch to moveit to release the movable switch member, and consequently the trippingcoil must be comparatively large and consume a comparatively greatamount of energy. The switches are, moreover, often arranged in sets tobe simultaneously opened by a single trip coil and, because ofthe'comparatively great amount of energy required to operate one latch,the size of trip coil to simultaneously operate all the latches must bemuch greater than is considered permissible.

lVhen a toggle member is employed in place of a latch to restrain themovable switch member in closed position, the toggle is arranged to beslightly over shot in order that the switch may remain in closedposition until opened. The electroresponsive tripping element isarranged, for the opening of the switch, to move the toggle into andslightly beyond the straightened or on-center position, whereupon themovable switch member, being no longer restrained in closed position,may move to open position.

The toggle member, to restrain the switch in closed position, alsorequires a comparatively great amount of energy to cause the switch tomove to open position, because it must be moved from the over shotposition into and beyond its straightened position.

A swltch restrained in closed position by a latch is also very sensitiveto mechanical shock or vibration. As there is a force constantly tendingto move the switch to open position, any shock or jar to the switchstructure, such as may often occur in the operation of machines inproximity to the switch, often'causes the latch to move the small amountnecessary to release the movable switch member and the switch maythereby be unnecessarily opened.

The toggle restrained switch is also subject to the same defect, as theover shooting of the toggle is usually made as small as possible inorder that the switch may be opened with but a small amount of energy.

The opening of the switch because of sudden jars or shocks is extremelyundesirable, and may even cause considerable damage to apparatusconnected to a circuit from which uninterrupted power service isrequired.

Consequently an object of my invention is in the provision of anelectrically controlled switch, in the closed condition of which thereis no force acting upon the movable member thereof to move said memberinto open position or into more fully closed position, whereby but asmall amount of energy is required to condition the switch for movementtoward open position.

A further object of myinvention is in the provision of means to locksaid switch in closed position against movement toward an open positionwhereby the switch will remain in such closed position until theoperation of the tripping means, and will be unaffected by any jars orshocks to which it may be subjected.

The means whereby I accomplish these objects of my invention is in theprovision of a toggle member to restrain the switch in closed positionand a latch to lock it in such' position. In the closed position of theswitch the toggle is arranged to be in its straightened or on-centercondition, and there is then no force acting upon the switch to moveit'toward an open position and but a very slight effort is necessary tomove the toggle the small distance required to permit the movable switchmember to move into open position.

The locking latch is provided with a projection normally restraining thetoggle from movement beyond straightened condition toward the opencondition of the switch, and

the switch structure is providedwith abutments to prevent over shootingof the toggle beyond the fully closed position of the switch.

The latch and abutment effectively prevent any movement of the togglemember and thereby securely hold the switch in closed position. As thetoggle is in its straightened condition or on center, but a slighteffort is necessary to cause the switch to move to open position. Theeffect of any movement of the latch, due to vibrations or shocks, iswithout effect on the switch because of the substantially on centerposition of the' toggle, and theswitchtherefore remains positivel inclosed position'until the tripping coil dl afinitely operates the latch.

A further object of my invention is in the design of a switch that isrelatively in expensive in construction, and yet entirely substantialand reliable in operation.

The means whereby I accomplish the object of my invention is in theconstruction of the switch mainly from stampings or punched parts,whereby the switches may be made in quantities with relatively smallunit expense and may be, at the same time, substantial and rugged.

A- yet further object of my invention is in the provision of a switchand tripping device therefor capable of being manufactured and assembledas separate units, and maintained in stock as such for assembling inproper relation on switchboard.

Figure 1 is a side elevation of a switch and tripping device thereforembodying my invention.

Fig. 2 is a front elevation of the switch.

Fig. 3 is a detail of the switch mechanism in open position.

F i 4 is a plan view of a switch contact mem er.

Fig. 5 is a sectional view of the contact member along lines 5--5 ofFig. 4.

Fig. 6 is a detail of the switch handle member.

Fig. 7 is a detail of the tripping coil and terminal connection.

Fig. 8 is a modified form of latch.

As here shown, the switch is mounted on the switchboard 9, and comprisesa housing formed of a single strip of material reflexed to provide thetwo parallel spaced apart standards 10 between which the component partsof the switch mechanism is arranged, the supportin feet 11 and crossconnecting strips 12, Sand su porting standards are secured to theswitchboard 9 by means of screws 13 screwed into the strip 12 and byscrew 14, in a manner hereinafter to be more full described.

The movable switch arm, pivoted at 15 to the housing, comprises a slnglestrip of material so formed as to provide a channel section 16' inwhich-the contact brush 17 is \secured, extended arm portions 18 whichare pivoted to the standards 10, andexteuded ears 19 by means of whichconnection is made to the operating handle.

The contact brush 17 is of usual construction, and is arranged, in theclosed position of the switch, to make contact with a stationary contact20 mounted upon the switchboard. An auxiliary contact 21, also of commonconstruction, is detachably secured to the resilient strip 22 carried bythe switch arm, and is arranged to make contact :with the auxiliarystationary contact 23. A second auxiliary contact 24, formed of a carbonblock, is connected with the stationary switch contact 20 and a secondcarbon block 25, secured to tho resilient strip 26 carried by themovable switch arm, is arranged to make contact therewith in the closedposition of the switch.

A spring strip 27 is secured to the mov able switch arm, and its tipportion bears upon the resilient strip 26, whereby additional resiliencyis imparted to the auxiliary carbon contact block carrier 26. Said brushmember 17 and the resilient strips 22, 26 and 27 associatedwith theauxiliary contacts are all secured to the movable switch arm by thebolts 28.

Switch operating links 29 are pivoted to the pin 30 extended between theears 19 of the movable switch arm and at 31 to the switch handle member32, which is pivoted at 33 to the switch supporting standard. The links29. and the switch handle member 32 form a toggle, by means of which themovable switch arm is moved between open and closed position. Saidswitch handle member is composed of a single strip of material andformed with two spaced parallel arms 34 and the connecting portion 35,and is disposed between the su porting standards 10 upon the pin 33. Sueof the arms 34 of said member is formed'with a cut out and refiexedportion 36 which, in the closed position of the switch, engages an edgeof the supporting standards 10 and thereby forms an abutment to preventfurther movement of the toggle mechanism beyond its on center orstraightened position, and the abutment is so arranged that in theclosed condition of the switch the toggle is on center.

The connecting portion 35 of the handle member is formed with a threadedopenin 37 therein and the handle 38 is rovide with a bolt 39 which isscrewed into this member, the said member and handle be1n locked againstremoval by the nut 40 secure to the end of said bolt 3 The parallelportions or arms 34 of the by spacing washers or rollers 47. The latchmember 44 is formed with an upright projection 48, which is arranged toengage with the latch roller 42 secured to the switch handle member inthe closed sition of the switch to maintain the movab e switch mem- 7her in'suelr elosed position.

The latch member 44 is formed with an extension or projection 49 on theopposlte side of the pin 46 over the upright extension 48, which ismaintained 1n normal engagement witha projection 50 formed in thetrlpping member 45. A spring 51 coiled about the pin 46, and having itsends in engagement with one of said standards 10 and said latch member44, serves to maintain the two portions of the latch in normalengagement.

The tripping member 45 1s formed with an end or nose portion 52, whichis arranged adjacent the latch roller 42. When said tripping member 45is moved upwardly under the action of the tripping means hereinafter tobe more fully described, said nose portion is arranged to engage thelatch roller 42 to move the toggle members from the1r on center positionto a osition beyond center, to thereby permit t e movement of the switchmember into open position. The movement of the tripping member alsoserves to remove the latch member from engagement with the latch roller,The tripping member is extended from ltspivot (pin 46 to a ponitadjacent the pin 15 exten ed between the standards 10 of the switchhousing, and is formed with twoprojections 53 which engage with said pin15 to limit the movement of the tripping member.

A modification of the latch is shown in Fig. 8, in which the latchmember and the tripping member are integrally formed 1n one piece. Asshown in this figure, the latch member is formed with a recess 56, inwhich the latch roller 46 is positioned in the closed condition of theswitch. A nose portion 57 is provided which, in the upward movement ofthe latch to trip the switch, engages with said roller 'to move .thetoggle members from on center or straightened position, to therebypermit the movement of the switch into open position.

The same movement of the latch serves to also withdraw the latch fromengagement with the latch roller.

In the closed position of the switch the toggle members are on center,and there is consequently no strain upon the latch, and the latch maytherefore be operated with a minimum of ener When the switch is subjectto shocks or jars caused by the vibration of the switch supports by anymeans, such shocks or 'ars wil not operate to open the switch. he latchmay be permitted a small amount of movement, due to the shocks or jars,but

is restricted from downward movement by the pin 15, and upward movementby engagement with the latch roller 42'. The permitted amount ofmovement is so small that the force with which the nose portion 57 ofthe latch is brought into engagement with the latch roller 42 isinsuflicient to cause the movement of the toggle members beyond straightcondition; and, moreover, the movement of the switch members isrestricted by the engagement of the latch roller with the wall of therecess 56.

A second stationary switch contact member is provided, with which thatportion of the brush member disposed within the supporting standards isarranged to make contact in closed position of the switch. Saidstationary contact member is composed of a single strip of sheetmaterial, and is formed with substantially parallel side portions 58 anda flat connecting portion 59. Said side portions or walls 58 of thecontact member are formed with slots or recesses 60 therein, in whichare adapted to be arranged the base portions 12 of the supportingstandard. The screw 14 is adapted to pass through an o ning in one ofsaid base portions 12, an to engage a threaded opening 61 in thestationary contact member, whereby said member is secured to theswitchboard 9.

Due to the disposition of said contact member about the base portion 12of the supporting standards, said standards are also secured to theswitchboard by the same screw 14. The flat top portion 59 of thestationary contact member forms a contact surface which is adapted to beengaged by the brush member 17 in the closed position of the switch.

A pig tail or flexible braid 62 is secured by means of the screw 63 tothe underside of the contact member, and extends through an opening 64therein to the channel portion 16 of the movable switch arm, where it isclamped by means of bolts 28 between the strips 26 and 27 Said pig tailforms an electric connection between the stationary. contact member andthe brush member 17, whereby s arking between the said members u on 't eopening of the switch is obviate The flat portion of said contact memberis formed with an extended car 65, with which connection is'adapted tobe made between the stationary contact member and the current coil ofthe overload tripping means. '5 3 The overload*trippin means includesthe L shaped core 66 for'me of laminated strips of iron secured in thesupport 67, which' is formed of non-magnetic material, and is fastened bmeans of bolts 68 to the switch board 9. aid support 67 is of channelsection, and is formed with extended end portions 69, between which themovable element 70 of the tripping means is-pivoted at 71. Said movableelement 70 is formed of magnetic material of L shape, and its endportion 72 is arranged in proximity with an end of the-stationary core66.

Said stationary core 66 and movable member 70 in the actuated conditionoi the tripping coil, form a substantially rectangular magnetic circuit,whichis incomplete at the pivotal end of the element 70 and at the end72 thereof. The end 74 of the core 66 is provided with a member 7 5formed of non-magnetic material of channel section, and downwardlyextended. Said member 75 is formed with a slot 76 in a face there; of,and an overload adjusting means is disposed therein.

Said overload adjusting means comprises a button 77 disposed on theouter face' of said member 75, and having a bolt or screw which projectsthrough the slot 76 and is in engagement with a nut or plate 78 movablyarranged within the channel portion of said member 75. Said adjustingmeans may be moved to any position in the slot 76 by partially rotatingthe button 77, whereupon-said button becomes unclamped from said member75, and can be moved to any desired position and reclamped in setposition by the partial rotation of the button'77 in the reverse sense,which operates to clamp the flat wall of said member 75 between thebutton 77 and nut or plate 78.

The end 72 of the movable element or armature 70 of the tripping meansis provided with a projecting pin 79 secured therein, and which extendsthrough the slot 76 of said member 75, and is movable therein. In thenormal or insufiiciently energized position of said armature or movablemember 70, the pin 79 rests upon the nut or movable plate 78 of the tripcoil adjusting means, and

y a movement of said adjusting means along the slot 76, the armature 70is moved nearer or farther away from the end 74 of thecore 66, andthereby varies the current value at which the trip coil will besufficiently energized to cause the movement of the armature 70 to tripthe switch. The member 75 may be provided witha calibrated scale 80,whereby the setting of'the adjustment may indicate the value of currentat which the overload tripping means will operate.

A strip 81 is secured by means of screws 82 to the armature 70 andextends under the latch '44 of the circuit breaker. A tripping pin 82 ofinsulating material is secured to the end of said strip 81 by means ofthe nut 83, and is arranged beneath the latch 44, to be brought intocontact therewith in the operated condition of the tripping means totrip the latch and open the switch. A button 85 is secured to thearmature 70, whereby said armature may be manually operated to cause theopening of the switch independently of its opening because of anoverload.

The current coil 86, as here shown, may be formed of a fiat strip ofmaterial edgew1se wound upon an insulating bushin 87 anddisposed overthe core 66. An en 88- of said coil is secured by means of the screw 89to the ear 65 of the stationary contact member and forms means wherebyconnection 1s made between said member to the tripping coil. The otherend 90 is arranged in a slot in the end of a rod 91, and may be securedtherein by sweating and by rivets 92. Said rod 91 projects through theswitchboard 9, and a washer 93 is disposed between said switchboard andthe end 90 of said coil 86, whereby said rod 91 forms one terminalof theswitch or circuit breaker, of which the rod or stud 94, secured to thestationary contact member 20, is the other terminal.

Although the tripping coil is here shown as comprislng a spirally woundstrip and is adapted for comparatlvely high values of current, yet it isobvious that for trip coils designed to operate between various rangesof current, the winding of the coil may be differently arranged in orderto be the most eflective for any particular range of current values. Allcoils are designed to be formed independently of the magnetic frame andto be arranged thereon, whereby a single magnetic structure may servefor venous coil windings.

I claim 1. In an electric switch, the combination with a movable switchmember, and a supporting housing therefor comprising spacedapartside-walls and spaced-apart side-wall connecting and supporting strips,of a stationar switch member disposed between said slde-walls and havingrecesses therein adapted to receive-said connecting and supill portingstrips, and means to secure said contact member to said housing and alsosecure said housing to a support. I

2. In an electric switch, the combination with a movable switch member,and a supporting housing therefor comprisingspacedapart side-walls andspaced-apart side-wall connecting and supportingi strips, of astationary switch member isposed between said side-walls and havingrecesses therein adapted to receive said connecting and supportingstrips, and means through one of said strips and engaging saidstationary switch member to secure said housing and stationary switchmember to a support.

3. In an. electric switch, the combination of a supporting housinghaving spacedapart side-walls and spaced-apart connecting-portions, anda stationary switch-member comprising a stamping having a fiat top walland side-walls with notches therein in which said connecting-portions ofthe housing are received.

1:. In an electric switch, a movable switch member, a switch housingbearing saidmovable switch member having spaced-apart standards andcross connecting stri s, a stationary contact member arrange within saidhousing above said cross connecting strips, means engaging one of saidcross connecting strips to secure said housing to a support, and meansextended through another of said cross connecting strips and engagingsaid contact member to secure said member and said housing to thesupport.

5. in an electric switch, a switch housing, a movable switch memberpivoted to said housing, a handle member pivoted to said housing, togglemembers connecting .said handle member with said movable switch member,said handle member being formed with a projection cut and extendedtherefrom to engage said housing in the fully closed position of theswitch to limit further movement of the movable member.

6. In an electric switch, a switch hous-' latch roller to cause amovement of theswitch toward open position, said latch being formed withprojections thereon engageable with said pivot pin, and said pin servingas a stop to limit the movement of said latch between normal andoperated positions.

7. In an electric switch, a movable switch member, means restrainingsaid member in extending closed. position, and a tripping device for iis received, a substantially L-shaped arma ture pivoted at one of itslegs to said membar and movable relative to said core, a sec- .ondchannel shaped member in the channel o which the other leg of said coreis received, said member extended'beyond said leg to receive saidarmature, a pin carried by said armature projecting through a slot inthe extended portion of said second channel' member, and a buttonadjustably arranged in said slot with which said pin is in normalengagement.

8. In an electric switch, stationary and movable switch-members, athreaded switch stud having an axially-disposed slot in its end, and atripping coil having a flat terminal fixed in the slot'in said stud withits side-portions extended on opposite sides beyond said stud to form ashoulder adante to engage a support for the stud.

9. In an electric switch, a movable switch member, an operating membertherefor connecting said members arranged on center to restrain theswitch in closed position, a. latch to lock said toggle from movementbeyond on center position in onedirection and an abutment to lock saidtoggle from movement beyond on center position in the other direction.

10. In an electric switch, a movable switch member, an operating membertherefor, mechanism connecting said members whereby a movement of saidoperating member serves to move said switch member into closed position,said mechanism being arranged in such closed position or" the switch, tobe without tendency to independently move said switch member from closedposition, a latch to lock'said mechanism from unintentional movement, atripping member engageable with said latch to remove it from lookingengagement with said mechanism and engageable with said mechanism tomove it to cause the opening of the switch, and means permittingindependent inovement of said latch and tripping mem- 11. In an electricswitch, a movable switch member, an operating member therefor, mechanismconnecting said members whereby a movement of said operating memberserves to move said switch member into closed position, said mechanismbeing arranged in such closed position of the switch, to be withouttendency to move said switch member from closed position, a latch tolock said mechanism from unintentional movement, and a tripping memberengageable with said latch to remove it from looking Mill engagementwith said mechanism and engageable with said mechanism to move it tocause the opening of the switch.

12. In an electric switch, stationary and movable switch members,operating mech anism comprising toggle-members. means to restrain saidtoggle-members from m0vement in an overshot direction whereby to holdthe switch closed, and a latch arranged normally to hold said togglemembers from movement in the opposite direction also arranged to releasesaid toggle members and forcibly move them in the opposite direction toopen the switch.

In testimony whereof, I have signed my 6 name to this specification, inthe presence of two subscribing witnesses.

DANIEL M. SCHIFFERT.

Witnesses T. T. GREENWOOD, H. B, 'DAVIS.

